PRINCETOWN, NY -

(AP) - Harley-Davidson's unveiling of its prototype electric motorcycle LiveWire is likely to give a boost to smaller companies already producing plug-in bikes.
    
Startups like Zero, Brammo and Mission are making state-of-the-art electric motorcycles on the West Coast.
    
A recent study by Navigant Research anticipates sales of electric motorcycles worldwide will grow to 1.2 million this year.
    
Electric motorcycles are well-balanced and easy to ride because most have direct drive, with gears and clutches optional.
    
There are no tailpipe emissions, no clunking pistons, no crankshaft, no oil leaks, no vibration and virtually no maintenance save new tires and brakes. The average range is well over 100 miles in city driving. And they plug into regular household outlets for charging that costs under $2.